Over 60% dengue cases untraced in Delhi, hurting mitigation work, say civic bodies

Dengue, malaria and chikungunya were declared “notifiable diseases” in the city under the Epidemic Diseases Act as per orders issued by the Delhi government on October 14, 2021.

The municipal corporations of Delhi are unable to trace the addresses of over 63% patients who were ill with dengue this year, according to official data. Of the 55 dengue cases reported this year till March 26, 35 cases have been marked as “untraced after investigation” due to incomplete or wrong addresses provided by patients and hospitals, a senior official from South Delhi Municipal Corporation (SDMC)-- the nodal agency for data compilation on mosquito-borne diseases-- said.

On March 29, 2022, SDMC issued a communication to hospitals, the department of health services and officials of the national vector-borne disease control programme red-flagging the issue. (HT Archive)

“For instance, in some cases, the hospital would mention the residential address as House Number 16, Rohini. Our field workers and zonal staff are not able to find the houses, which are then categorised as untraced after investigation. In such cases, we cannot carry out fogging, undertake the administration of anti-larvae insecticides or carry out awareness activities to control the spread in that locality,” a senior public health official of the north municipal corporation said.

Dengue, malaria and chikungunya were declared “notifiable diseases” in the city under the Epidemic Diseases Act as per orders issued by the Delhi government on October 14, 2021. While more hospitals--their number has increased from 36 to 180 from September to February--are reporting cases now due to the notification, incomplete/wrong data is defeating the purpose behind the move, officials said.

On March 29, 2022, SDMC issued a communication to hospitals, the department of health services and officials of the national vector-borne disease control programme red-flagging the issue.

The letter, a copy of which HT has seen, said that dengue is a major health concern in the country, which accounts for substantial morbidity and mortality, and it is mandatory for medical institutions to notify cases to municipal health authorities so they can take containment measures. “Hospitals are requested to notify confirmed cases within 24 hours along with accurate information such as patient details, residential addresses and contact numbers,” the letter said.

The problem, however, is not a new one. Several dengue cases have been untraceable in the last five years. Last year, Delhi had recorded 9,613 dengue cases and 23 fatalities in 2021, making it the second-worst annual outbreak on record. Municipal records show that around one-third of these cases (2,971 out of 9,613 ) were marked as untraced. In 2020, 15.57% (167 out of 1,072 cases) of reported dengue cases were untraceable, while 47.34% dengue cases (964 out of 2,036) were marked untraceable in 2019. The untraceability ratio was even higher in 2018 when addresses of over 70% (2,798 out of 3,566) reported cases could not be traced.

Meanwhile, the public health departments of civic bodies are also working to increase the reporting network of the hospitals. “Deputy health officers have been directed to map all nursing homes and hospitals so that dengue reporting can be improved. All big and small healthcare outlets where fever patients are being treated will be mapped and linked to an integrated health information portal,” a north MCD official explained, adding that the city has moved from sentinel surveillance to mandatory reporting, making it statistically impractical to compare pre-2021 and post-2021 data.